Max-Thrust Ruckus current consumption?

[Jeffrey Cottrell 2]

Hi Guys

Ruckus had its maiden today. Best classed as adequate without setting the world on fire.
Did reveal a puzzle, and a couple of things to think about.
So, the puzzle:
Fitted the ZTW 50a esc. Took a bit of head scratching, because it is considerably thicker than the Century one.
Ended up making a ply plate, glued to the esc, then Velcro'ed to the fuz side. Means I can get it out the way to fit the battery. Might have a re-think on that later.
The puzzle is this.
With the new esc, ran the same prop tests as with the old one. Each test gave noticeably higher current readings.
On the 11 x 5.5 4s, old current was 38a new one 45a, increase of 7a.
10 x 5 on 4s, old 27a, new 31a up by 4a.
12 x 6 on 3s, old 31a, new 34a up by 3a.
Might just be my (very old) wattmeter getting tired. Ordered a new one from 4-Max, so I'll defer judgment until I get that, but it does seem odd that all three props showed a sizeable increase in current drawn.
So, to the test flight:
Out of deference to the measured currents I went for 12 x 6 on 3s. Take off was fine, but it did seem to lack straight line speed, even on full throttle. This made rolls a bit 'squirrelly' not as snappy as I would like.
Mind you, did potter around quite happily on half throttle or less, but I really didn't want 'potter'. Some work to do there.
Did a 5 minute check flight, then measured the charge put back in. Surprisingly only 633Ma, which calculates to an average current of only 7.6a.
Oh dear, something very amiss there.
Also noticed that throughout the flight the model was flying tail down, this even on the glide. Landing was 'interesting'. However low and slow I came in, the model seemed to float all the way along the strip, without wanting to lose any height. Even a complete deadstick, and glide in produced the same result. Eventually ran off the end of the strip and into long grass, happily no damage.
My thought is either the c/g too far back, or an incidence issue between wing and tail.
Anyway, waiting for the new meter to arrive, maybe might shed some light.
Any thoughts on the tail down attitude?
Thanks
Jeff

[Jeffrey Cottrell 2]

Hi Guys
Not sure if anyone's still following my random musings, but this may be of interest.
Took the Ruckus out again today.
Not sure if I believe the 45a reading I got before, so, caution to the winds, set up on 4s with 11 x 5.5 prop.
As expected, the performance was much improved with the higher power system. Very similar to my Riot, so pleased with that.
Did a 5 minute check flight. Charger put back in 697Ma to a 2650 pack, which calculated out to be some 8.4a average.
Now comes the fun bit.
After coming back from the field found the postie had been left, amongst other things, my new watt meter from 4-Max.
Plugged that up and did another static test. Gave same 45a flat out.
So, my original test was ok, gives my old Irvine ammeter a clean bill of health.
Still no reason why a change of esc should give such a change in WOT current.
Any thoughts?
Jeff

[Dickw]

55 minutes ago, Jeffrey Cottrell 2 said:

Hi Guys
Not sure if anyone's still following my random musings, but this may be of interest.
.........................................................
Still no reason why a change of esc should give such a change in WOT current.
Any thoughts?
Jeff

 

 

Several possibilities.

Did you calibrate the Tx and the ESC settings to ensure the ESC is reaching full throttle?

Could the connectors of the “low current” ESC be a bit high resistance?

Check the soldering of the connectors and cables on the “low current” ESC.

 

Dick

Edited March 31, 2021 by Dickw

[Kim Taylor]

53 minutes ago, Jeffrey Cottrell 2 said:

Hi Guys

Still no reason why a change of esc should give such a change in WOT current.
Any thoughts?
Jeff

Possibly the original esc hadn't properly calibrated to the stick??

Either that or it's some kind of electronic witchcraft and the new esc is better able to handle the current, or maybe the old one was current limiting as it neared it's maximum.

Kim

eta I see Dickw has beaten me to the punchline!!?

[Kim Taylor]

Btw further to my 12x8e prop on a 3s pack experiment, I flew all morning yesterday after double checking the current at 36A and no issues at all, other than the extra strain killing one cell in one of my packs. The motor and esc were no more than warm to the touch and the performance was noticeably better than with the stock 12x6e.

Knocked about 2 minutes off of the duration when using the extra performance of course, but you don't get ow't for now't, or so they say.

Kim

[SIMON CRAGG]

Jeff,

 

Just sent you a pm.

 

Simon

[Chris Walby]

IMO

Sorry, I just don't get it. The RIOT is trainer, RUCKUS follow on trainer, made to a price, jack of all trade master of none. That's it and you'll never make a silk purse out of them.

They are not made to be repeatedly taken apart and reassemble.. just repaired.

It is what it is and if you want fast, get something that goes fast (EFX Racer), if you precision buy a SEBART, but I can't see the point of whining about it....the more effort and time you spend trying to improve the less you will actually achieve.

 

Leave it as is, accept that, fly the the nuts off it and move on to something else.    

[Kim Taylor]

2 hours ago, Chris Walby said:

IMO

Sorry, I just don't get it. The RIOT is trainer, RUCKUS follow on trainer, made to a price, jack of all trade master of none. That's it and you'll never make a silk purse out of them.

They are not made to be repeatedly taken apart and reassemble.. just repaired.

It is what it is and if you want fast, get something that goes fast (EFX Racer), if you precision buy a SEBART, but I can't see the point of whining about it....the more effort and time you spend trying to improve the less you will actually achieve.

 

Leave it as is, accept that, fly the the nuts off it and move on to something else.    

I have to say, I tend to agree - it is what it is!!

Kim

[SteveHyde]

On 25/03/2021 at 13:50, Jeffrey Cottrell 2 said:

Hi Guys

Shaun

Sounds like my Riot on 4s. 6' take off roll then vertical climb to the cloudbase. Wouldn't want to do it all the time, but huge fun when I do.

Out of interest, which motor did you use for the upgrade?

Steve

That sounds a bit of a high pitch for this model. How did you come by that figure?

Was going to ask how it flew, but then I read your other post about the u/c collapsing. Not good.

Was yours the ready covered version. If so, could it be a manufacturing fault (not enough glue) rather than a design flaw.

Like Earlybird, would like some pictures of the damage.

For mine, I have a 55a esc on order, but not sure if it will arrive before flying starts again, so I have set mine up on 3s with a 12 x 6 prop to keep current draw in the safe zone.

Here's hoping

Jeff

I tried  a 12x 8 prop. It did not give the power to get off the ground.  There for the change in pitch.  I repaired the undercarriage with lots of apoxy and wood. Still failed on first landing.  Reworked with carbon copy wot4 undercarriage.  Wheels slightly forward of the revised fixing . Lands fine now on tarmac runway.  Still lacks power and will not loop using  the 3300 4s batteries. 

[Jeffrey Cottrell 2]

Hi Steve

That's surprising. What motor do you have in there?

Jeff

[SteveHyde]

On 25/03/2021 at 13:50, Jeffrey Cottrell 2 said:

Hi Guys

Shaun

Sounds like my Riot on 4s. 6' take off roll then vertical climb to the cloudbase. Wouldn't want to do it all the time, but huge fun when I do.

Out of interest, which motor did you use for the upgrade?

Steve

That sounds a bit of a high pitch for this model. How did you come by that figure?

Was going to ask how it flew, but then I read your other post about the u/c collapsing. Not good.

Was yours the ready covered version. If so, could it be a manufacturing fault (not enough glue) rather than a design flaw.

Like Earlybird, would like some pictures of the damage.

For mine, I have a 55a esc on order, but not sure if it will arrive before flying starts again, so I have set mine up on 3s with a 12 x 6 prop to keep current draw in the safe zone.

Here's hoping

Jeff

 

[SteveHyde]

I came up with the prop  size as it is as recommended by the motor manufacturer. 

[Jeffrey Cottrell 2]

Hi Guys

Just a quick add-on.

Did my first test flights with the Ruckus on 4s 11 x 5.5 prop. Just come back from a couple of tests with a 10 x 5 prop and I can't really see any degrading in performance. 

Just to check, I fitted the same prop to my Riot and got the same result.

Main thing, now, is a static test of consumption read only 32.5a, so well within the comfort zone of the supplied esc. Must be getting close to the sweet spot.

Cheers

Jeff

[Mitchell Howard]

On 24/03/2021 at 18:00, Frank Skilbeck said:

ZTW Beatle ESCs are my go to ESC at the moment, not had one fail yet.

 

sorry to reply to an old-ish thread, but I wondered Frank if you knew anything about the ZTW Mantis controllers - I see they're described by ZTW as the step up from entry-level Beatles ones. I gather there's more throttle linearity - have you ever tried one?

[Mitchell Howard]

On 13/04/2021 at 19:19, Jeffrey Cottrell 2 said:

Hi Guys

Just a quick add-on.

Did my first test flights with the Ruckus on 4s 11 x 5.5 prop. Just come back from a couple of tests with a 10 x 5 prop and I can't really see any degrading in performance. 

Just to check, I fitted the same prop to my Riot and got the same result.

Main thing, now, is a static test of consumption read only 32.5a, so well within the comfort zone of the supplied esc. Must be getting close to the sweet spot.

Cheers

Jeff

 

What capacity 4S are you using Jeffrey?

 

[Jeffrey Cottrell 2]

Hi Mitchell

I'm using these. First started using them on my Riot and they transformed it from mediocre to a load of fun. Since the Ruckus uses the same power train, they were the natural choice.

I do know they're only 20c, but I have never noticed any degrading in performance. Given that some 'c' claims are a fiction anyway, why pay more for something you might not even have (cheapskate, moi?)

Hope this helps

Jeff

P.S. Can't comment on the Mantis controllers. I do have something running the Beatles one, and it's been fine. However I do have a Voltigeur on 4s using one of these. Been faultless in operation so far, and for £18 or so can't be beat. 5a bec as well.

J

[Mitchell Howard]

3 minutes ago, Jeffrey Cottrell 2 said:

Hi Mitchell

I'm using these. First started using them on my Riot and they transformed it from mediocre to a load of fun. Since the Ruckus uses the same power train, they were the natural choice.

I do know they're only 20c, but I have never noticed any degrading in performance. Given that some 'c' claims are a fiction anyway, why pay more for something you might not even have (cheapskate, moi?)

Hope this helps

Jeff

P.S. Can't comment on the Mantis controllers. I do have something running the Beatles one, and it's been fine. However I do have a Voltigeur on 4s using one of these. Been faultless in operation so far, and for £18 or so can't be beat. 5a bec as well.

J

 

My 3700 4S Zeee packs weigh 304g vs the 265g of the Turnigy

Turnigy dims 137 x 44 x 22mm

Zeee dims 138*48*23mm

 

Looks like they'll be alright - did you have to do any serious chiseling to get the CoG right?

 

Looks like prop down to 10x5" to do a static load test as a starting point.

[Jeffrey Cottrell 2]

Hi Mitchell

Just done a real world check on those dimensions. As usual, HK have them wrong, but this time in our favour.

So, for length read 134mm, width 42mm, and height 21mm. Also weight is 255g, not 265g. Not a great difference but might be handy for a tight install.

No chiselling at all to get the c/g right. Started off using a 3s 3000 pack, pushed right forward as far as the foam will allow. Given the 2650 4s is much the same weight, just slid it as far forward as it would go and flew it like that. I know c/g position can be subjective, depending how you want the model to fly, but after numerous flights haven't felt any pressing need to change it.

Couple of other thoughts.

Century got it a little bit wrong, in that they supply an 11 x 5.5 prop in the kit, but don't tell you that's for a 4s set up. If you're running a 3s, you would need a 12 x 6 at least. Anyway, I tried mine first with the supplied prop, and it flew very well, and current within limits.

Never being one to leave well enough alone, I tried the 10 x 5 as an experiment. Static current was noticeably reduced, as should be, but subjectively I noticed very little difference in performance.

If you want, start with the supplied prop, see how you like it, and then switch to the 10 x 5 see if you notice any difference. I'm betting, very little if at all.

Sounds to me like you already have the packs, so this might not interest you.

I use those same 2650 packs on my Voltiguer. Flies that with authority, no issues, but I did notice after a 7 min flight that the charger put back in some 2100 ma, so a bit close the the 80% safety limit.

So, treated myself to one of these. 137mm x 44 x 21 and 262g, so pretty close to the 2650's.

Came from EU warehouse so took a little while, but well worth the wait.

Slightly higher 'c' rating, 30 instead of 20, but noticeably better performance. Verticals were good, now excellent, but the main thing is, with the 2650's level flight took about half throttle. With the 3000's now that is well below half. After 7 min flight, charger put back 1700 ma or so, so consumption much improved, which was the name of the game.

Next time out, I'm going to try the NT pack on the Ruckus, see if I can pull the wings off.

Jury still out on long term. Nanotechs have a reputation for puffing after very few flights, but time will tell.

So far, so good.

Jeff

 

[Frank Skilbeck]

9 hours ago, Mitchell Howard said:

 

sorry to reply to an old-ish thread, but I wondered Frank if you knew anything about the ZTW Mantis controllers - I see they're described by ZTW as the step up from entry-level Beatles ones. I gather there's more throttle linearity - have you ever tried one?

 

Sorry no, not tried a Mantis, but as I still fly lots of glow models I most ESCs have better throttle linearity ?

[Andy Gates]

A few comments for you.

 

Beatles ESC take quite a beating.

I have 2 x 60A units - one on 3S one on 4S.

On 3S I routinely pull 70A in up lines from ground to 400ft, extra cooling in the form of a stick on heat sink has been added just in case but always comes down slightly warm as does the motor as there is plenty of cooling air.

On 4S at WOT I am a bit over the 60A limit and it has no access to cooling - so I have added extra cooling in the form of a stick on heat sink. Again no real issues.

 

Differences between ESC's may be down to timing set up on the units - nowt to worry about.

 

Nanotech battery packs have so far been pretty good for me, I don't overstress them and so far they have not blown. I have some of the blue Turnigy packs which have now blown but still seem to perform OK but they are now 5-6years old and have had frequent usage.

[Andy48]

16 hours ago, Frank Skilbeck said:

 

Sorry no, not tried a Mantis, but as I still fly lots of glow models I most ESCs have better throttle linearity ?

What does that mean? Thrust linearity or current linearity?

[Mitchell Howard]

44 minutes ago, Andy48 said:

What does that mean? Thrust linearity or current linearity?

 

I should imagine thrust and current increases occur linearly together anyway, but my throttle linearity understanding is how the ESC responds to the input at the Tx throttle stick.

 

Say you take 10s to move from 0 to 100% WOT. On my Beatles, one of the very first things I noticed when I was a rank beginner was how the tone of the motor was not completely smooth, i.e. the output to the motor is done in bands. For example, perhaps I get 5% revs between 5-10% stick position, 10% revs between 10-15% stick position. Maybe there's 10 speeds between 0-100% stick position. I'm guessing, I've not listened and counted. Fellow club members said this was normal.

 

The Mantis is described as;

"The ZTW Mantis series is designed as a performance upgrade for your stock/OEM ESC. Its performance, feature set, and stability make it the perfect enhancement for your RC electric airplane or helicopter. It features compact size, light weight, simplified PCB design, super-smooth start up and throttle linearity, multiple circuit protections, governor, high amp BEC output and more. If you want to boost the performance of your stock ESC, the ZTW Mantis is an ideal choice offering a long list of advanced features and solid, reliable construction."

 

I take this to mean that maybe there's 20-30 speeds for 0-100% stick position. Certainly enough to feel like it's linear.

 

Do I need it? No probably not! Do I want it? Yes! Why? I don't know! Proportional stuff is supposed to be proportional!

 

Edited July 22, 2021 by Mitchell Howard

[Andy48]

12 minutes ago, Mitchell Howard said:

 

I should imagine thrust and current increases occur linearly together anyway, but my throttle linearity understanding is how the ESC responds to the input at the Tx throttle stick.

 

 

On the tests I've done, the throttle is linear to the static thrust, but current consumption is not even close to being linear. As an example, with a 3548 size motor and a 12x6 prop, its about 15-18 amps at half throttle and 1kg static thrust, at full throttle its 50+amps and 2.2kg static thrust. Telemetry in the air gives similar current consumptions.

 

Here's a good example. The current is shown in green, throttle position in red. At full throttle the current peaks about the same, nearly 50 amps, but at half throttle the current is far lower. If the two were linear, then both curves would match at all throttle positions.

 

[Frank Skilbeck]

15 hours ago, Mitchell Howard said:

 

I take this to mean that maybe there's 20-30 speeds for 0-100% stick position. Certainly enough to feel like it's linear.

 

 

 

I must admit I have never noticed the effect you are discussing (and I use a slow start on many electric gliders), but it would probably be more difficult to program a step change into a speed controller. The way and ESC works is by switching the voltage on/off to the coils very quickly when the magnets are in the correct position, the duration of the on period being proportional to the PPM signal into the ESC.

 

Maybe the best way to test this would be to set up a test measuring, volts, amps and rpm as the throttle is opened, I'll see if I can set something up and run such a test.

 

(BTW I will probably start a new thread on this)

[Jeffrey Cottrell 2]

Hi Andy

Thanks for the graphs. Bears out what I've been finding by a more roundabout route.

I don't have telemetry to help, so I do a static test to see if I'm close to blowing anything, then go fly.

What I do is to do a timed flight, I usually use 7 minutes, of mixed flying. Some fast some slow, some s&l, some hooligan.

After that I note what the charger puts back in, then some maths gives me the average current through the flight.

Case in point.

I was trying my Ruckus on 4s.

Static test showed 32.5a, so well within the comfort zone, but average current in flight came out at some 12a or so. Far less than I was expecting.

All good.

As an aside, anyone else with a Ruckus, if you haven't already, bung a 4s in there, it will transform it.

One point.

Most esc's when you first start, require you to teach it where 0% and 100% throttle are. Generally, you power up with the stick fully up, then when it bleeps pull the stick to low.

Minor point, but might affect both overall current and linearity.

Cheers

Jeff